A method of displaying a three-dimensional (3D) object includes acquiring a driving image from a single camera, classifying line marks including a road surface into one or more groups based on a change in a curvature of a line of the road surface, estimating a pitch angle corresponding to an angle of inclination between the road surface and the single camera for each of the one or more groups, generating 3D information of the road surface, and displaying an 3D object visually overlaid on the road surface based on the 3D information of the road surface.